Sense 1opportunity, chance -- (a possibility due to a favorable combination of circumstances; "the holiday gave us the opportunity to visit Washington"; "now is your chance") => possibility, possibleness -- (capability of existing or happening or being true; "there is a possibility that his sense of smell has been impaired")

Sense 2luck, fortune, chance, hazard -- (an unknown and unpredictable phenomenon that causes an event to result one way rather than another; "bad luck caused his downfall"; "we ran into each other by pure chance") => phenomenon -- (any state or process known through the senses rather than by intuition or reasoning)

Sense 3chance -- (a risk involving danger; "you take a chance when you let her drive") => risk, peril, danger -- (a venture undertaken without regard to possible loss or injury; "he saw the rewards but not the risks of crime"; "there was a danger he would do the wrong thing")

Sense 4probability, chance -- (a measure of how likely it is that some event will occur; a number expressing the ratio of favorable cases to the whole number of cases possible; "the probability that an unbiased coin will fall with the head up is 0.5") => measure, quantity, amount -- (how much there is or how many there are of something that you can quantify)

Sense 1chance -- (be the case by chance; "I chanced to meet my old friend in the street") => happen, hap, go on, pass off, occur, pass, fall out, come about, take place -- (come to pass; "What is happening?"; "The meeting took place off without an incidence"; "Nothing occurred that seemed important")

Sense 2gamble, chance, risk, hazard, take chances, adventure, run a risk, take a chance -- (take a risk in the hope of a favorable outcome; "When you buy these stocks you are gambling") => try, seek, attempt, essay, assay -- (make an effort or attempt; "He tried to shake off his fears"; "The infant had essayed a few wobbly steps"; "The police attempted to stop the thief"; "He sought to improve himself"; "She always seeks to do good in the world")

Sense 3find, happen, chance, bump, encounter -- (come upon, as if by accident; meet with; "We find this idea in Plato"; "I happened upon the most wonderful bakery not very far from here"; "She chanced upon an interesting book in the bookstore the other day")